Low profile cable tie with prebent strap

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/855,414, filed May 15, 2001 now U.S. Pat. No. 6,560,822.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to a low profile cable tie with a bent cable strap. More particularly, the invention relates to a two-piece cable tie with a lateral strap accepting channel in the cable tie head and a prebent right angle strap attached thereto.

2. Description of Related Art

Plastic cable ties, and in particular plastic cable ties having metal locking device inserts, are well known in the art. Examples of such include U.S. Pat. No. 3,457,598 to Mariani and U.S. Pat. No. 5,517,727 to Bernard et al.

Cable ties of this type, referred to as two-piece cable ties, are generally illustrated by FIGS. 9 and 10 and include a metal locking device <b>910</b> partially embedded at an angle within a strap accepting channel <b>920</b> of a cable tie head <b>930</b>. The metal locking device <b>910</b> is situated at an angle that allows insertion of a cable tie strap <b>940</b> in an insertion direction, but allows for engagement of the locking device <b>910</b> with the strap when it is pulled in a removing direction to prevent removal. The metal locking device of such conventional cable ties is in the form of a cantilevered beam that is fixed at one end and extends into the strap accepting channel at the free end.

As shown in FIG. 10, these conventional two-piece cable ties have a strap accepting channel perpendicular to a longitudinal axis of the head. That is, the channel exits a top surface of the cable tie head as shown. In such designs, the large open space on the top surface of the cable head necessary to enable insertion of the metal locking device makes the appearance unclean. Also, when bundling a cable bundle <b>950</b>, the conventional two-piece cable tie may interfere more with other cable bundles or objects because the head of the cable tie extends too far beyond the cable bundle periphery (i.e., to the left and above the cable bundle as shown in FIG. <b>10</b>).

There is a need for an improved two-piece cable tie that has a lower profile.

There is a further need for a cable tie having a clean, aesthetic exterior appearance.

There is yet a further need for a two-piece cable tie that can achieve a reduced installation size to minimize space constraints for the tie. That is, a reduction in height and width attainable when installed on a cable bundle.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a two-piece cable tie having a low profile locking head with a lateral strap accepting channel and a prebent right angle strap.

It is another object of the invention to provide a two-piece cable tie having a clean exterior appearance, including a top surface free of openings and a smooth lateral opening.

It is a further object of the invention to provide a two-piece cable tie with a strap accepting channel that extends tangential to a cable bundle and is nearer the cable bundle when installed.

It is yet a further object of the invention to provide a two-piece cable tie having a low profile locking head with a lateral strap accepting channel and a prebent right angle strap attached thereto.

It is yet another object of the invention to provide a cable tie with a strap accepting channel parallel to a longitudinal axis of the head while having an entrance channel that can accommodate insertion of a strap end over a greater angular range and accommodate the width of the strap to minimize overall cable tie dimensions during use.

One or more of the above and other objects are achieved by a low profile cable tie, comprising: a strap having a predetermined thickness and including a first end that is molded with a right angle bend and a free end; a locking head including a strap accepting channel in the head that divides the locking head into a first part and a second part, the strap accepting channel having a strap entry end and a strap exit end on opposite ends of a strap accepting channel axis, the first part of the locking head being secured to the first end of the strap along a strap attachment axis which is substantially parallel with the strap accepting channel axis, the locking head further including a locking device receiving cavity located on the second part adjacent to and open toward the strap exit end of the locking head; and a locking device mounted within the locking device receiving, the locking device including a free end angled at an acute angle relative to the strap accepting channel axis and extending into the strap accepting channel. A top surface of the locking head is provided immediately adjacent the locking device and has a thickness extending above the locking device that is no more than the thickness of the strap and where the first part has a thickness that is no more than the thickness of the strap. The locking device is preferably a metal locking device.

One or more of the above and other objects of the invention may also be achieved by a low profile cable tie, comprising: a strap having a predetermined thickness and including a first end and a free end; a locking head including a strap accepting channel in the head that divides the locking head into a first part and a second part, the strap accepting channel having a strap entry end and a strap exit end on opposite ends of a strap accepting channel axis, the first part of the locking head being secured to the first end of the strap along a strap attachment axis which is substantially parallel with the strap accepting channel axis, the locking head further including a locking device receiving cavity located on the second part adjacent to and open toward the strap exit end of the locking head; and a metal locking device mounted within the locking device receiving cavity, the metal locking device being mounted within the locking device cavity by having a fixed end mounted to a mounting slot in an internal wall of the second part, the fixed end being oriented substantially parallel to the strap accepting channel axis, the metal locking device further including a bent free end angled at an acute angle relative to the strap accepting channel axis and extending into the strap accepting channel. The locking device is preferably a metal locking device.

One or more of the above and other objects may further be achieved by a method of forming a low profile cable tie, comprising the steps of: molding a cable tie strap with a predetermined thickness, the strap having a first end with a substantially right angle bend in a non-use state and a free end; forming a locking head secured to the first end of the strap, the locking head including a strap accepting channel having a strap entry end and a strap exit end aligned along a strap accepting channel axis, the strap accepting channel dividing the locking head into a first part and a second part, the first part of the locking head being secured to the first end of the strap along a strap attachment axis which is substantially parallel with the strap accepting channel axis, the locking head further including a locking device receiving cavity located in the second part of the locking head adjacent to and open toward the strap exit end of the locking head; forming a locking device with a fixable end and a free end that is angled at a predetermined acute angle relative to the fixed end; and providing the locking device in the locking device receiving cavity of the second part of the locking head so that the free end of the locking device extends into the strap accepting channel and the fixable end is securely fixed to the second part.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein:

FIG. 1 is a bottom perspective view of a cable tie according to the present invention;

FIG. 2 is a bottom view of a cable tie according to the invention;

FIG. 3 is a cross-section view of the cable tie of FIG. 2 taken along line <b>3</b>—<b>3</b>;

FIG. 4 is a cross-sectional view of a locking head of the cable tie of FIG. 3 taken along line <b>4</b>—<b>4</b>;

FIG. 5 is a cross-sectional view of the cable tie showing an initial feeding of the strap into a strap accepting channel;

FIG. 6 is a cross-sectional view of the cable tie of FIG. 5 after the strap has been fully inserted and locked in place around a bundle of cables;

FIG. 7 is a cross-sectional view of the cable tie of FIG. 5 after the strap has been fully inserted and locked in place around a single cable;

FIG. 8 is a partial cross-sectional view of the cable tie of FIG. 1 better showing details of the strap entrance;

FIG. 9 is a side view of a conventional two-piece cable tie; and

FIG. 10 is a cross-sectional view of a conventional two-piece cable tie locked in place around multiple cables.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

An inventive cable tie <b>100</b> will be described with reference to FIGS. 1-8. Cable tie <b>100</b> includes a locking head <b>102</b> and a strap <b>104</b>. Cable tie <b>100</b> can be made from various materials as known in the art. Suitable materials include by way of example, nylon, polypropylene, and various fluoropolymers. Cable tie <b>100</b> can be formed in various sizes and lengths to suit a particular application as also known in the art. Obviously, desired loop tensile strength is one factor to decide when selecting sizing of the strap, locking head and other components.

Locking head <b>102</b> includes a strap accepting channel <b>122</b> and a locking device receiving cavity <b>180</b>, both extending substantially parallel to a longitudinal axis P of locking head <b>102</b>. Strap accepting channel <b>122</b> is provided to receive strap <b>104</b> and includes a strap entry end <b>168</b> through which strap <b>104</b> is first inserted and a strap exit end <b>166</b> (see FIG. 3) through which strap <b>104</b> exits. The strap entry and exit are oriented along axis P. As best shown in FIGS. 3-4, strap accepting channel <b>122</b> is formed by an end wall <b>124</b>, a bottom wall (exterior wall) <b>126</b>, and side walls <b>128</b>. Strap accepting channel <b>122</b> has a predefined width sufficient to receive strap <b>104</b> and may be provided with a support guide <b>114</b> including a ledge <b>116</b> protruding from bottom wall <b>126</b>. As best shown in FIG. 8, a leading edge <b>126</b>A of bottom wall <b>126</b>, in the region of the strap accepting channel <b>122</b>, is inset from the full length L of locking head <b>102</b> by an inset distance I. As such, bottom wall <b>126</b> has a length L-I. Inset I is preferably greater than the thickness T of strap <b>104</b>. Advantages of such a structure will be discussed below when describing operation of the cable tie.

Referring back to FIG. 1, strap <b>104</b> includes a first end which is fixedly attached to and bent closely adjacent a lower corner of locking head <b>102</b> at approximately a right angle to axis P. That is, the first end is formed with a right angle bend, which bend is essentially retained in a static non-use state. Strap <b>104</b> has a predefined thickness and further preferably includes standard gripping ridges <b>108</b> (see FIG. 3) on the outside surface of an angled and tapered second free end <b>112</b> of strap <b>104</b>. Strap <b>104</b> may be provided with a longitudinally extending central groove <b>110</b> on the inside surface as shown in FIGS. 1-2. Central groove <b>110</b> may have an increased width, such as by providing a V-groove <b>120</b>, near the first bent end as best shown in FIGS. 1-2.

As best shown in FIG. 3, strap accepting channel <b>122</b> divides the locking head <b>102</b> into a relatively thin first part (shown to the right of channel <b>122</b>) that attaches to the first end of strap <b>104</b> and a second part (shown to the left of channel <b>122</b>) that contains the locking device receiving cavity <b>180</b>, and which receives a locking device <b>136</b>. Cavity <b>180</b> is adjacent to and open toward the strap exit end <b>166</b> of the locking head to allow access for partial embedding of locking device <b>136</b> in a mounting slot <b>130</b> of end wall <b>124</b> to define a cantilever beam structure having a fixed end <b>134</b> and a free end <b>138</b> that extends into strap accepting cavity <b>122</b>. Locking device receiving cavity <b>180</b> also allows for movement of locking device <b>136</b> during use. Mounting slot <b>130</b> may be preformed in an interior surface of cavity <b>180</b> or may be formed as a result of pressing an end <b>134</b> into the surface of endwall <b>124</b>. An opening <b>132</b> may be provided between mounting slot <b>130</b> and interior wall portion <b>142</b>.

This structure is useful in attaining a low profile cable tie due to several individual features. First, by orienting the strap accepting channel <b>122</b> as shown, the channel can be located tangential to the cable tie bundle being bound. Further, as the locking device is provided on the second part, the first part (which includes bottom wall <b>126</b>) can be made thinner. This allows the strap when inserted through the strap accepting channel <b>122</b> to be closer to the cable bundle. While some minimum thickness is required for structural rigidity, it is possible to make bottom wall <b>126</b> the same thickness or even less than that of strap <b>104</b> (thickness T in FIG. <b>8</b>). To further minimize the profile, the top outer surface <b>146</b> above the locking device <b>136</b> that forms a top of the cable tie head is preferably made to be thin and has no upwardly extending projections. This surface may extend above the locking device by a thickness that again can be less than the thickness of strap <b>104</b>. The particular size of the strap may vary depending on application. When the locking device <b>136</b> is a metal locking device, the profile can be further reduced from the conventional two-piece design shown in FIGS. 9 and 10 by providing a bent locking device as shown in FIG. 3, with a fixed part <b>134</b> that is substantially parallel with the strap accepting channel. This minimizes the required height of the locking device receiving cavity <b>180</b> and thus assists in reducing overall cable tie head height. Further, by making the top surface smooth and free of upward extending openings, the cable tie is less likely to snag on, abrade or interfere with adjacent wires or cable ties. This can be further assisted by rounding the edges as shown.

Locking device <b>136</b> is preferably formed from a corrosion resistant metal, such as stainless steel, as known in the art. While locking device <b>136</b> may take a conventional straight form, it is preferably bent or formed so that free end <b>138</b> (mounted end) is at a predetermined angle relative to fixed end <b>134</b>. This allows for a reduction in cable head height and thus achieves a lower profile head. Moreover, by providing a prebent locking device <b>136</b>, easier insertion of locking device <b>136</b> into cavity <b>180</b> can be attained. In any case, free end <b>138</b> extends into the strap accepting channel at an acute angle relative to the axis of strap accepting channel <b>122</b> facing strap exit end <b>166</b> and the locking device <b>136</b> is provided on the second part of the locking head <b>102</b>.

During non-use, cantilevered metal locking device <b>136</b> is located adjacent a fulcrum point defined by an upper edge of interior wall <b>142</b>. Metal locking device <b>136</b> has a free length defined from the fulcrum point to free end <b>138</b> that allows free end <b>138</b> to extend into channel <b>122</b> by a distance to sufficiently engage strap <b>104</b> and prevent withdrawal of the strap from the channel.

Use of the inventive cable tie to bundle or wrap one or more cables <b>170</b> will be described with reference to FIGS. 5-7. FIG. 5 shows initial insertion of leading end <b>112</b> of strap <b>104</b> into leading end <b>168</b> of strap accepting channel <b>122</b>. Due to the provision of the inset of an end surface <b>126</b>A of bottom wall <b>126</b> by a distance I (best shown in FIG. <b>8</b>), the leading end <b>112</b> of strap <b>104</b> can be inserted over a broad range of entrance angles. This facilitates easier positioning of leading end <b>112</b> within channel <b>122</b>. Moreover, when strap <b>104</b> is inserted at steep angles relative to axis P, as illustrated by the rightmost strap in FIG. 5, the overhanging portion of inner wall <b>124</b> reliably receives and guides the leading end <b>112</b> into channel <b>122</b>. This further assists in reliable operation of the cable tie.

Insertion continues from that shown in FIG. 5 to that shown in FIG. 6, where the strap <b>104</b> has passed metal locking device <b>136</b> and metal locking device <b>136</b> has begun biting into the strap to restrain the strap from removal. At this point in time, cable tie <b>100</b> is sufficiently tight around an object to be constrained, such as cable bundle <b>170</b>. Strap <b>104</b> may be self-aligned in strap accepting channel <b>122</b> by the mating of central groove <b>110</b> around support guide <b>114</b> as shown. For this example, portions of leading end <b>112</b> extending beyond exit end <b>168</b> of locking head <b>102</b> have been shown cut and removed. However, the leading end may also be retained.

By provision of this inset I, the effective height or thickness of the channel entrance <b>168</b> can be increased without increasing total height of locking head <b>102</b> or making the remaining thickness or height of the channel much larger than the thickness of strap <b>104</b>. This assists in achieving an overall low profile head design.

By locating the locking device <b>136</b> on the top side of the locking head (second part of the locking head opposite the first part that is secured to strap <b>104</b>), the strap accepting channel <b>122</b> can be located closer to the bundle. Moreover, by use of a bent locking device, the second part of the locking head can have a reduced height, which further assists in achieving a low profile cable tie design.

While being able to accommodate a large bundle of cables <b>170</b>, the inventive cable tie <b>100</b> is also able to accommodate a very small bundle, or even a single cable <b>170</b>. This is shown in exemplary FIG. 7 where a single cable <b>170</b> is constrained by cable tie <b>100</b>. Due to the bent first end of strap <b>100</b>, flexing occurs at the bend and the strap can either expand to accommodate receiving a large cable bundle (as in FIG. 6) or can closely conform to the small cable <b>170</b> (as in FIG. <b>7</b>). Moreover, by provision of inset I and the low profile head <b>102</b>, free end <b>112</b> of the strap can be inserted to closely conform to cable <b>170</b>. It is preferable for inset I to be the same or larger than the thickness of strap <b>104</b> so that the strap in use during the strapping of a very small bundle of cables may not stick out beyond the overall length of the cable tie locking head <b>102</b> as measured along the strap accepting channel axis. This achieves a cable tie structure which when in use can achieve a minimal peripheral profile compared to conventional two-piece cable ties such as that shown in FIG. <b>9</b>. That is, the cable tie <b>100</b> does not extend much beyond the periphery of the cable (in width) due to the bent strap end, the inset I, and the strap accepting channel orientation, and does not extend much beyond the periphery of the cable (in height) due to the low profile head design, which is achieved by various combinations of the strap accepting channel orientation, the thin first part of the locking head, and a bent metal locking device.

While the systems of the invention have been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.